Someone told me recently, that he keeps all his data in the cloud. All his kids pictures, his documents, everything. And he doesn't do a backup.
I was horrified. And told him so. "But surely MyCloud (I made up that name, I forget who it actually was) will be doing backups?"
Yes, probably. Maybe. I expect so. But that isn't the problem.
Suppose the people running MyCloud, suddenly decide that your pictures are all in violation of someone's copyright? Or that they violate their "Acceptable Use Policy". And so then remove them all.
Well, they aren't a violation of copyright, you took the photos yourself. OK. But how are you going to fight the MyCloud people? A lawsuit? You know what that would cost?
Or suppose the FBI decide to impound all of MyCloud's computers, for some reason that they think is a good one?
Or suppose some hacker got your password and deleted all your files?
All of these things have happened, and could happen again.
So I convinced him to use his DVD writer and burn himself a copy of everything that's important to him.
Because your data isn't yours until you can hold it in your hand.